Le 04/06/2016 20:19, Paul A. Rubin a écrit :
Kiuhnm <kiuhnm2015 <at> gmail.com> writes:
I'm using Lyx 2.1.4. I'd like to write a bunch of inequalities with an
\iff on the right side. The inequalities should be centered, like this:
<centered inequality1> <=>
<centered inequality2> <=>
<...>
Does the appended LyX file do what you want? I used the alignat environment,
and increased the number of columns to five. The left side of each
inequality goes in column 1, the inequality symbol in column 2, the right
side in column 4 and the iff symbol in column 5. Column 3 is intentionally
blank.
Paul
#LyX 2.2 created this file. For more info see http://www.lyx.org/
\lyxformat 508
\begin_document
\begin_header
\save_transient_properties true
\origin unavailable
\textclass article
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\language english
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\font_osf false
\font_sf_scale 100 100
\font_tt_scale 100 100
\graphics default
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\index_command default
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\spacing single
\use_hyperref false
\papersize letterpaper
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\use_package amssymb 1
\use_package cancel 1
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\use_package mathtools 1
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\use_package stackrel 1
\use_package stmaryrd 1
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\cite_engine basic
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\use_indices false
\paperorientation portrait
\suppress_date false
\justification true
\use_refstyle 1
\index Index
\shortcut idx
\color #008000
\end_index
\leftmargin 1in
\topmargin 1in
\rightmargin 1in
\bottommargin 1in
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\paragraph_separation skip
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\end_header
\begin_body
\begin_layout Standard
\begin_inset Formula
\begin{alignat*}{3}
ax & \le & & b & \iff\\
cx+d & \ge & & e & \iff\\
d+2e & = & & 3f+g
\end{alignat*}
\end_inset
\end_layout
\end_body
\end_document
What about
\begin{align*}
a & \leq b\tag*{\ensuremath{\iff}}\\
b & \geq a\tag*{\ensuremath{\iff}}\\
a & \leq b
\end{align*}
?
(\ensuremath was added automatically by LyX)